There was absolutely no more need to have additional officers or innocents slain by this thug. I thank them for ending it right then and there as opposed to having to spend literally millions of dollars to prosecute him and then keep his sorry hide alive for 40 years.
The United States of America is supposed to operate under the rule of law, not the law of the jungle.
Justice is to administered in a courtroom, and that's what separates us from the savages.
While I understand your emotions, there is no reason for the process to be circumvented. There's a name for a nation where judgement is rendered by the police: It's called a Police State. That, sadly, is where we are headed. This is just one example out of thousands.